1998 Science Highlights: Microgravity Research

Science In Space

Rise and shine

A challenge in developing advanced materials, such as superalloys, is attaining a precise understanding of the physical properties of the materials when they are molten and taking their final form. However, contact between the material and its container can alter or completely mask those properties. What is needed is a facility that suspends the materials for study while molten. In 1998, NASA/Marshall acquired a sophisticated Electrostatic Levitator.

Right: A 3 mm droplet of molten nickel-zirconium hovers between electrodes inside the ESL during an experiment.

The ESL, directed by Dr. Jan Rogers, uses static electricity to suspend an object inside a vacuum chamber. While that happens, a laser heats the sample until it melts, so scientists can record a wide range of physical properties without contact with the container. An array of sensors measure properties such as viscosity, surface tension, and specific heat. The ESL complements NASA/Marshall's Drop Tube Facility, and expands support for even more sophisticated experiments using space-based facilities.

NASA also continues work on other systems that can process materials without disruption by containers or handling equipment.

1998 Science@NASA stories It floats - New tool levitates molten materials - The Electrostatic Levitator, donated by Loral Space Systems to Marshall Space Flight Center, uses static electricity to suspend small samples in this next generation of ground-based containerless processing. Levitating furnace holds promise for future experiments - A unique levitation furnace that flew on the Space Shuttle is 1998 is being eyed for upgrades to fly on future Shuttle and International Space Station missions..

Soft as a baby's breath

The structure of an antibody crucial to fighting the Respiratory Syncytial Virus (RSV) was refined during 1998 by using proteins grown as crystals on a 1997 Space Shuttle mission. RSV is a serious, potentially deadly, disease that usually strikes infants and young children. More than 4 million cases a year are reported, with more than 4,000 infants dying from it. Understanding the structure of the RSV antibody will help scientists develop pharmaceuticals that help the body fight the disease faster and more efficiently.

Right: Young children will benefit most from drugs to fight RSV.

Knowing structure of proteins is important to understanding their function, and then tailoring drugs for a specific function without side effects. It's like making a key to fit a lock. Proteins can be grown as crystals so their structure can be revealed through X-ray crystallography. Because of the mass of these large molecules, growing well-ordered crystals is difficult on Earth. The active region of the RSV antibody has been defined, which will help scientists to develop smaller, more easily made molecules that have the same therapeutic effect.Research in space has helped scientists start to learn the structures of a number of crucial proteins - including the RSV antibody - in the quest to improve life on Earth.

1998 Science@NASA stories Breathing easier, living longer are goals of Shuttle experiments. Protein crystal growth experiments continue on STS-95. Nov. 3, 1998. STS-89 will carry five science payloads from NASA/Marshall. with link plus the date and a one-line summary.

Terra (not always) firma

Anyone who has seen a "solid" brick of vacuum-packed coffee flow upon opening or watched a building sink during an earthquake has witnessed soil liquefaction. This occurs when the effective stresses on a soil are reduced almost to zero, and the grains can easily move past each other. Studying the mechanics of soil and of powders in industrial processes under these conditions has been blocked by the effects of Earth's gravity pulling on grains in what is usually a transient event.

Right: A CT-scan reveals structures inside a cylinder of sand squeezed while in space. Colors indicate areas of strain.

The Mechanics of Granular Materials (MGM) experiment, directed by Dr. Nicholas Costes, uses the low-g of space to manipulate standardized sand samples under low-effective stresses that cannot be achieved on Earth. The STS-89 Space Shuttle mission carried MGM and six test cells on a range of experiments that provided experimental data with applications to in fields as diverse as controlling soil erosion on river banks and designing wheels for better traction on Mars.

1998 Science@NASA stories Soil mechanics experiment yields unique results - Shuttle experiments yield new information on how soil and powders behave like liquids under low pressure like those experienced during earthquakes or the manufacture of cosmetics. May 27, 1998. Soil mechanics make clean sweep - All six test cells were processed in an experiment to study the movement of powders, grains, and dirt in the low-gravity conditions of space. The science team is hopeful that the success of this mission, and its anticipated data, will lead to a third mission to explore soil mechanics further. Feb. 4, 1998. Putting the squeeze on sand will expand understanding of soil mechanics - MGM will fly on STS-89 in late January. Results of research have direct application to earthquake engineering, coastal engineering, off-road vehicle technology and other fields. Jan. 6, 1998.

Keeping your cool

The work of Sojourner, the mini-rover that explored Mars in 1997, was made easier by using Aerogel, a silicon dioxide gel. Its weight is nearly zero, yet the insulation provided by its myriad nanoscopic cells is equivalent to 20 to 30 panes of ordinary windows. Aerogel also could fuel new growth in the computer industry. The challenge to making ever fast computers in the 21st century perhaps raising desktop computers from today's 300 MHz speed to a whopping 24 GHz hinges not on smaller transistors but on better ways to keep wires from shorting across the narrow space between them.

Right: A thin section of Aerogel protects a rose from the heat of a Bunsen burner. Aerogel has tremendous promise as a thermal and electrical insulator.

That's where Aerogel, as the best solid dielectric ever created, may contribute. These potential uses are hindered by variations in gel pore sizes; some are small enough to scatter blue light (just as dust gives the sky its blue color). To help realize Aerogel's potential, SSL is investigating how different conditions affect Aerogel's formation. In October 1998, the STS-95 Space Shuttle mission carried a large, advanced Aerogel experiment facility to test forming techniques for Dr. David Noever. In it, 16 pairs of syringes, joined at the nozzles, mixed the solutions mixed for a preset number of cycles. The product is being analyzed now at Marshall.

1998 Science@NASA stories Right Stuff for the Super Stuff. John Glenn will conduct tests with a space age super-substance called aerogel on STS-95. Oct. 26, 1998. One small switch for a man... John Glenn will activate an experiment later today that could revolutionize the computer industry and much more. Oct. 30, 1998. NASA Aerogel web site with technical information and historical background.

Breast cancer cell research

Breast cancer is one of the most frightful diseases that face women in modern society. Of the 180,000 women who are diagnosed with it each year, about 45,000 die. One of the keys to understanding how breast cancer tumors grow is understanding how healthy breast cells grow. In early 1998, SSL established a facility to conduct research on the growth of healthy and cancerous breast cells. It employs a unique cell collection of breast tissue harvested from a cancer-susceptible woman who elected to have a double mastectomy.

Right: Cells for breast cancer research are preserved in liquid nitrogen dewars until needed for culturing in NASA Bioreactors.

Dr. Robert Richmond is culturing cell lines in NASA Bioreactors, a unique device that had its origins at NASA/Marshall in the 1980s. Cells refuse to grow normally for long in ordinary flat-dish cultures. In the Bioreactors, both healthy and (in future work) tumor cells form lifelike constructs as they grow and differentiate much as they would in a healthy body. This will help determine the intercellular conditions that might slow or even stop the growth of breast tumors. Because the cancer susceptibility of these cells, the collection lends itself to research on radiation shielding for long-term missions, another NASA/Marshall endeavor.

1998 Science@NASA stories NASA using space incubator to understand breast cancer - Bioreactor research could help women's health on Earth and in space. Oct. 1, 1998.

Clear communications

Equipment to pull fibers of a promising optical fiber was completed for aircraft experiments in early 1999 and orbital tests aboard the Space Shuttle. ZBLAN, a heavy-metal fluoride glass (fluorine joined with zirconium, barium, lanthanum, aluminum, and sodium [Zr, Ba, La, Al, Na]) could be a nearly perfect transmitter of infrared through ultraviolet light. This would enable the large bandwidth communications that 21st century society will demand, plus medical and manufacturing applications. However, ZBLAN fibers made on Earth form crystals that act as mirrors that reflect light and obliterate a signal.

Right: A ZBLAN fiber pulled in weightlessness is clear as glass, the ideal for laser communications. Fibers pulled under 1-g usually form crystals that scatter light.

Tests aboard a rocket (1996) and an aircraft (1997) demonstrated that fibers can form in low-g without crystallizing. In 1998, a team led by Dr. Dennis Tucker of Marshall Space Flight Center's Space Sciences Laboratory constructed and began testing a preform processor, and redesigned a laser scattering apparatus for detecting crystallization as fibers form. Both are scheduled for flight tests aboard a NASA low-g aircraft in February 1999 as a final validation of the designs for space flight experiments. These are planned for 2000 to test orbital preparation of boules for fiber pulling on Earth, and for 2001 to pull a 2 km-long fiber in a proof-of-principle demonstration.

1998 Science@NASA stories ZBLAN continues to show promise. Thin fibers of an exotic glass called ZBLAN are clearer when made in near weightlessness than on Earth under gravity's effects. Feb. 5, 1998.